//
//  ESP_WifiUtil.m
//  Snap
//
//  Created by 小猪向天飞 on 2018/7/7.
//  Copyright © 2018年 Facebook. All rights reserved.
//

#import "ESP_WifiUtil.h"

#include <ifaddrs.h>
#include <arpa/inet.h>
#include <net/if.h>

#define IOS_CELLULAR    @"pdp_ip0"
#define IOS_WIFI        @"en0"
#define IOS_VPN         @"utun0"
#define IP_ADDR_IPv4    @"ipv4"
#define IP_ADDR_IPv6    @"ipv6"

@implementation ESP_WifiUtil

+ (NSString *)getIPAddress:(BOOL)preferIPv4
{
  NSArray *searchArray = preferIPv4 ?
  @[ IOS_VPN @"/" IP_ADDR_IPv4, IOS_VPN @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6 ] :
  @[ IOS_VPN @"/" IP_ADDR_IPv6, IOS_VPN @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4 ] ;
  
  NSDictionary *addresses = [self getIPAddresses];
  //    NSLog(@"addresses: %@", addresses);
  
  __block NSString *address;
  [searchArray enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop)
   {
     address = addresses[key];
     if(address) *stop = YES;
   } ];
  return address ? address : @"0.0.0.0";
}

+ (NSDictionary *)getIPAddresses
{
  NSMutableDictionary *addresses = [NSMutableDictionary dictionaryWithCapacity:8];
  
  // retrieve the current interfaces - returns 0 on success
  struct ifaddrs *interfaces;
  if(!getifaddrs(&interfaces)) {
    // Loop through linked list of interfaces
    struct ifaddrs *interface;
    for(interface=interfaces; interface; interface=interface->ifa_next) {
      if(!(interface->ifa_flags & IFF_UP) /* || (interface->ifa_flags & IFF_LOOPBACK) */ ) {
        continue; // deeply nested code harder to read
      }
      const struct sockaddr_in *addr = (const struct sockaddr_in*)interface->ifa_addr;
      char addrBuf[ MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN) ];
      if(addr && (addr->sin_family==AF_INET || addr->sin_family==AF_INET6)) {
        NSString *name = [NSString stringWithUTF8String:interface->ifa_name];
        NSString *type;
        if(addr->sin_family == AF_INET) {
          if(inet_ntop(AF_INET, &addr->sin_addr, addrBuf, INET_ADDRSTRLEN)) {
            type = IP_ADDR_IPv4;
          }
        } else {
          const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6*)interface->ifa_addr;
          if(inet_ntop(AF_INET6, &addr6->sin6_addr, addrBuf, INET6_ADDRSTRLEN)) {
            type = IP_ADDR_IPv6;
          }
        }
        if(type) {
          NSString *key = [NSString stringWithFormat:@"%@/%@", name, type];
          addresses[key] = [NSString stringWithUTF8String:addrBuf];
        }
      }
    }
    // Free memory
    freeifaddrs(interfaces);
  }
  return [addresses count] ? addresses : nil;
}

+ (NSString *)getIPAddress4
{
  NSString *key = [NSString stringWithFormat:@"%@/%@",IOS_WIFI,IP_ADDR_IPv4];
  NSString *ipv4 = [[self getIPAddresses]objectForKey:key];
  return ipv4;
}

+ (NSString *)getIpAddress6
{
  NSString *key = [NSString stringWithFormat:@"%@/%@",IOS_WIFI,IP_ADDR_IPv6];
  NSString *ipv6 = [[self getIPAddresses]objectForKey:key];
  return ipv6;
}

@end
